DE3220865C2 - Pressure-sensitive adhesive based on polymer mixtures containing hydroxyl groups - Google Patents

Abstract

For the contracting States BE, CH, DE, FR, GB, IT, LI, LU, NL, SE 1. Contact adhesive based on cross-linkable resin mixtures liquid at temperatures below 100 degrees C, based on hydroxyl group-containing polymers with a molecular weight of 500 to 30,000, preferably 1000 to 10,000, characterized in that 5 to 90 mol % (preferably 10 to 80 mol %) of the hydroxyl groups present originally in the mixture have been replaced by the reaction product of an organosilane of the general formula see diagramm : EP0096249,P12,F1 with a monomeric or polymeric di- or triisocyanate. For the contracting State AT 1. Process for the production of cross-linkable resin mixtures with a molecular weight of 500 to 30,000 which are liquid at temperatures below 10 degrees C, and for their associated cross-linking, characterized in that hydroxyl group-containing polymers are reacted either a) with a diisocyanate in the molar ratio NCO:OH of approximately 2:1, there action product being produced is reacted with the stoichiometric amount of an amino or mercaptoalxoxy silane, corresponding to the free NCO- groups, and the reaction product is mixed with sufficient OH-group-containing polymers that the ratio OH:alkoxy silyl groups is less than or equal to 1:0,9 or b) with the addition product of equimolar amounts of amino or mercaptoalkoxy silanes with diisocyanates in such amounts that the ratio OH;NCO is less than or equal to 1:0,9 and then the cross-linking is carried out.

Description

that at least one of the starting polymers present in the mixture has a glass transition temperature of less than + 20 ° C and that 5 to 90 mol% of the hydroxyl groups originally present in mixture A) by the reaction product from an organosilane of the general formula

R ₁ -NH-R ₂ -Si

(OR ₄ ),.,

or

(R ₁ ).

HS - R ₂ - Si

3ύ Ri = H or alkyl. Cycloalkyl. Aryl. Aralkyl.

R ₂ = Ci-Cialkylene

R ₃ = methyl or ethyl

R4 = alkyl or alkoxyalkylene with up to 4 carbon atoms

η = 0 or 1 or 2
35

have been replaced with a monomeric or polymeric di- or triisocyanate.

2. PSA according to claim 1, characterized in that the polymers contained in the mixture terminally or statistically distributed hydroxyl groups and groupings of the general formula

Ri (Rj).

-OCO-NH-R ₁ -NH-CO-NR ₂ -Si

N) R ₄ ) or

-OCO-NH-R _x -NH-CO-SR ₂ -Si '

\ ι!

(OR ₄ ), -,

contain. R, = remainder of the monomeric or polymeric diisocyanate used for the preparation. ί | ·

Dukten 3. The use of pressure sensitive adhesives according to claims I or 2 for the production of f selbslklebenden product. ΐ

The present invention relates to solvent-free or low-solvent adhesive on the basis of heatable, Resin mixtures based on hydroxyl groups that are liquid at temperatures below 100 ° C Polymers with a molecular weight of 500 to 30,000.

For the production of self-adhesive products, an adhesive / coating in liquid form must be applied suitable substrate can be applied. The liquid state is mostly obtained by dissolving or by dispersing of the adhesive achieved in solvents or in water. For the drying of the giggles so applied layer, a correspondingly high expenditure of energy is necessary. It also requires the use of organic Solvents in larger quantities for environmental reasons either incineration of the discharged solution or the operation of a solution recovery failure. To avoid these disadvantages we would like to Solution-based adhesive has also already been developed. Such solvent-based pressure-sensitive adhesives contain either

the reactive system or are made by applying the adhesive from the melt, i.e. by means of a so-called Hot-melt adhesive, received.

Because of the many difficulties encountered with active pressure-sensitive adhesives, these systems have so far not been able to establish themselves commercially. Hotmelt pressure-sensitive adhesives, in particular those based on block copolymers of styrene and isoprene or butadiene, as described for the first time in US Pat. No. 3,239,478, have been much more successful. Adhesive adhesives of this type, however, still have a few shortcomings: The most important disadvantage is the purely thermoplastic character of the material: the cohesion of the adhesive at elevated temperature, the so-called thermal shear strength, quickly decreases with increasing temperature. On the other hand, the material must be applied at temperatures mostly well above 150 ^° C. in order to bring the melt viscosity into the low range required for the coating process. In addition, the material has a very moderate resistance to atmospheric oxygen. Heat, high-energy radiation (e.g. UV) and against solvents.

To avoid the disadvantages mentioned, the following proposals have already been made: In DE-PS 27 36 952 the block copolymer is selectively hydrogenated in order to achieve better heat and aging resistance achieve. According to the procedure described in DE-OS 30 25 247, the addition of a Copolyester of the mixture of block copolymers and tackifier resin. better solvent resistance awarded. According to US Pat. No. 4,133,731, an improvement in cohesion is achieved by graft polymerization achieved by (meth) acrylic acid esters under UV or electron beam curing. The same goal is through Addition of polyphenyl ether resin in US-PS 41 41 876 described procedure followed

Notwithstanding these numerous efforts, however, it has not yet been possible to produce hot-melt pressure-sensitive adhesives with properties herzusialen.die those of applied from organic solution only to some extent equivalent would be.

The numerous reactive pressure sensitive adhesive systems that are described in the literature have a number of options of reasons so far not found practical use. Although it is already known by reacting with Water or humidity or by heating to higher temperatures crosslinking and thereby the for Adhesive to achieve the desired increase in cohesion. So is in DE-AS 20 20 496 by heating 120 ° C crosslinking of polymers containing carbo * yl groups by cation exchange or expulsion of Ammonia effects; this method is hardly attractive for large volume users of pressure-sensitive adhesives. By Moisture-crosslinking pressure-sensitive adhesives are described in JP-PS 54-64 536: Copolymers of (Meth) acrylic acid esters with maleic anhydride contain fine-grained oxides (e.g. ZnO or PbO) and harden with humidity with salt formation. The disadvantage of this method lies in the insolubility of the oxides in the polymer, which allows a finely divided, but always only heterogeneous suspension of the hardener.

The task for the present invention was. Adhesive adhesive with the following profile of properties to develop:

1. poor or entirely solvent-free

2. Can be used at the lowest possible temperature

3. by a crosslinking reaction that is contained in the coating process in a state essential bring increased consistency

4 in the crosslinked state as high as possible cohesion, even at temperatures of up to 200 ⁰ C.

5. good inherent tack

6. good aging resistance.

This object is achieved by a pressure sensitive adhesive on the basis of cross-linkable, at temperatures below 100 ⁰ C liquid resin mixtures of polymers hydroxylgruppcnhaltigen mii a molecular weight from 500 to 30,000, which is characterized. that it consists of

A) the liquid resin mixture, if appropriate

B) suitable catalysts and, if appropriate, accelerating the crosslinking reaction

C) suitable, inert diluents such as solvents, plasticizers, pigments and fillers,

that at least one of present in the mixture Ausgangspolyirtere has a glass transition temperature of less than +20 ⁰ C, and that 5 to 90 mol% of the originally present in the mixture A) hydroxyl groups by the reaction product of an organosilane of the general formula

R ₁ -NH-R ₂ -Si

HS -R ₅ -Si

(OR ₄ ) j- _n

R ₁ = H or alkyl. Cycloalkyl, aryl, araicyl
R ₂ = Ci-Csalkylene
R ₃ = methyl or ethyl

R ₄ = alkyl or alkoxyalkylene with up to 4 carbon atoms
5/7 = 0 or 1 or 2

have been replaced with a monomeric or polymeric di- or triisocyanate.

The stated object is achieved in that one of hydroxyl group-containing flowable Polymers or polymer mixtures goes out and proportionally through the hydroxyl groups present in the mixture

ίο the reaction product of monomeric or polymeric di- or triisocyanate is substituted with a suitable organofunctional alkoxysilane. Mixtures formed in this way, which accordingly contain both hydroxyl groups and alkoxysilane groups, can be stored well at room temperature and in the absence of moisture. They can be processed at temperatures of up to 100 ^° C. without difficulty, ie without any appreciable increase in viscosity, and can then either be processed by the action of moisture

or by heating to temperatures of over 100 ^° C., preferably over 120 ^° C., are crosslinked. Both the curing conditions and the properties of the end products can be varied over a very wide range by appropriate selection of the starting products.

The two alternatives to hardening, i.e. H. the hydrolysis of the alkoxysilane groups with the formation of Siloxane bonds or intermolecular transesterification at elevated temperature can each be used on their own

be carried out completely. It is also possible to partially carry out one hardening reaction and then continue the other. The degree of crosslinking of the end product can be adjusted via the silane content without there being any incompatibility between crosslinking and nHureacting polymer molecules.
The invention can be carried out in a variety of ways. In principle, a hydroxyl group-containing

term polymer, which at room temperature or moderately elevated temperature (below 100 ° C) in the liquid state

is available as an initial maierial. Poly (terpolyols) are particularly suitable. Polyether polyols. Polyetherester polyester

lyole. functional glycerides and partial glycerides (e.g. castor oil or castor monodiglyceride) or hy-

hydroxy-containing polybutadienes and polyvinyl-acrylic acid ester copolymers.

Correspondingly, the molecular weight of the starting products is below 20,000, in the majority of cases below

10,000. Only in the case of poly (meth) acrylic acid ester copolymers can a molecular weight of up to 30,000 still be present. At least one of the starting polymers present in the mixture must have a glass transition temperature (Tg) of less than + 20 "C, with very low glass transition temperatures - ie less than -10 ⁰ C - having an advantageous effect on the properties of the end product, ie the pressure-sensitive adhesive.

The alkoxysilanes can be introduced into the polymer molecules in various ways. An advantageous one Implementation consists in the reaction of the polymers mentioned with diisocyanates and such organofunctional silanes that are capable of reacting with isocyanates, each with an NCO group the silane and reacts with an OH group of the polymer. Aminosilane sterols are particularly suitable for this, but also mercaptosilane esters and others with sufficiently reactive hydrogen atoms. The Rcaktionsiolge is

not decisive. it must only be ensured that no unintentional increase in molecular weight he follows. The following reaction sequences are also possible:

A. Level 1: 1 mole of organofunctional silane + 1 mole of diisoeyanul

Stage 2: OH-containing polymer or polymer mixture + aclduct from stage I in such a mixture. that on an OH group at most 0.9 OCN groups is absent.

B. Stage 1: OH-containing polymer + diisocyanate, whereby one. to avoid undesirable MoIe

kular weight increase will choose a molar ratio of NGO: OH of almost 2: 1.
Stage 2: Implementation of this prepolymer from stage 1 with the stoichiometric amount of an organofunctional silane star mentioned above.

Stage 3: Mixture of the product from Stage 2 with such an amount :; of OH-containing polymers that im

resulting mixture of the sum of the hydroxyl and alkoxys'lyl groups present therein at most 90% are allotted to alkoxysilyl groups. The polymer used for this can

both starting products from stage 1 as well as another compatible polymer of the above group.

In principle, all known and commercially available monomeric or polymeric diisocyanates are suitable Diisocyanates, whereby stage I can be omitted through the use of a polymeric diisocyanate in sequence B.

The use of tri-isocyanates is also possible in principle. When used, it must only be ensured that no undesired increase in molecular weight occurs.
As organofunctional silanes are aminosilane esters of the general formula

^b5 R ₁ -NH-R ₂ -Si '

(R ₃ ),

R ₁ = 11 or alkyl, cycloalkyl. Aryl, aialkyl

R. = C 1-4 alkylene

Ri = methyl or ethyl

R ^ = alkyl or alkoxyalkylene with up to 4 carbon atoms

η = ο or I or 2 ■>

suitable, particularly those with only one - preferably secondary - amino group. Examples are:

/ -Aminopropyltrimethoxysilane; - aminopropyltrielhoxysilane

N-methyl - ^ - aminopropyltrinictrioxysilane

N-cyclohexyl / aminopropyltrimethoxysilane

N-n-Octyl -> "- Aniinopropyltriinethoxysiiun

N-phenyl-; '· aminopropylirimethoxysilane Di- [1-propy! -3 (trimcthoxysilyl)] amine

N-methyl - / - aminopropylmethyl-dimethoxysilane.

(Rj),
HS-R ₃ -Si

(OR ₄ ), -, -'s

in the R ₂ . Rj and R _{4 have} the abovementioned meaning, such as ι. B.

/ • Mercaptopropyltrimethoxysilane

/ -Mercaptopropyltriethoxysilane: to

are useful in practicing the invention.

In addition to methoxy and ethoxysilane, there are also other alkoxy substitutes, in particular the monomethyl ethers of glycols such as ethylene or diethylene glycol etc. can be used.

The curing of the products after application can take place in various ways:

For crosslinking by hydrolysis, it is particularly advantageous that, in the case of coatings, naturally a large Surface is formed when a material is applied in a thin layer. The Cross-linking with humidity at room temperature. A substantial acceleration can be achieved suitable hydrolysis catalysts known from the literature, such as tin, titanium compounds or amines achieve. Brief treatment with superheated steam is particularly effective.

Crosslinking by applying temperature begins at about 100 ° C. and takes place ^{rapidly at temperatures above 120 °} C. It is also accelerated by suitable catalysts such as dibutyltin dilaurate or other known transesterification catalysts low alcohols out of balance, as long as this does not naturally happen by itself, as is the case with thin-layer application.

While this is not advantageous in the case of hydrolysis hardening, low molecular weight substances can also be used in the case of thermal hardening Di- or polyols are used as chain extenders.

As already stated above, the choice of the molar ratio of hydroxyl groups to alkoxysilane groups is important Variable over very wide limits: in the case of hydrolysis hardening, over-crosslinking should only be avoided in order to avoid the disadvantages mentioned at the beginning. In practice, therefore, a molar ratio of Choose OH to alkoxysilane groups from 1.0 to <0.9, i.e. H. the hydroxyl groups of the polymers are at least to 5 mol% and not more than 90 Mo! -% replaced by alkoxysilyl groups. For thermal hardening can it is assumed that a trialkoxysilane can react with up to three hydroxyl groups, while for example a dialkoxyalkylsilane can only react with up to two hydroxyl groups. It will therefore be the case for the person skilled in the art not difficult to set the desired degree of crosslinking. In general, you will therefore also work for the thermal curing has a molar ratio of hydroxyl to alkoxysilyl groups of 1 to Select <0.9.

Of course, the products according to the invention can be mixed with suitable inert diluents such as Solvents, plasticizers, pigments and fillers are provided, provided these are sufficiently low Have moisture content, so that the storage stability of the preparations is not adversely affected will. In practice, the amount of solvent will be less than 10% by weight.

The products according to the invention are outstandingly suitable for the production of adhesive tapes, self-adhesive labels and other self-adhesive finished products.

The implementation of the invention is described in detail in the following examples:

TO ÖDÜ

Examples Λ. Components used

1. Polyesters The following polyesters were produced from the dicarboxylic acids or glycols given below

1'CS 1

PI-S

PtS J

I'ES 4

Composition (mol%) terephthalic acid isophthalic acid Orthophthalic adipic acid

Egg yoglyko! Neopentyl glycol, hexanediol-1,6 trimethylol propane

Properties: Glass transition temperature. ° C Mol.wt. OH number

2. Polyester blends The following blends were produced from the polyesters listed under!:

- 35 - H
\ i - - 35 - - - - 79 - 100 30th 21 100 54 21 -ih 14th 83 79 14th 29 - _ 30th 3 17th - - -56 + 17 + 10 -59 approx. 3,000 2,000 1,700 2,000 35 95 60 55

PUS-M I PKS-M 2 PES-M 3 composition
(in parts by weight)
PESI
PES 2
PES 3
PES 4 100
100 100
25th 40
100 Characteristics:
Glasiemp., ° C
OH number -38
76 -49
43 -16
77 Viscosity, m Pa · S
25 "C
80 ⁰ C 319,000
3,150 90,600
2,790 11,660,000
22,800 3. polyether

A branched polypropylene glycol with a Functionality of 3. OH number 32 to 36 and an average molecular weight of 4,900 are used.

4. Harder

In the following, a hardener is understood to mean the constituent of the resin which has the alkoxysilyl end group contains.

4.1 Adduct of S-isocyanatomethyl-S.S.S-trimethyl-cyclo-hexylisocyanai (also called isophorone diisocyanate and hereinafter referred to as IPDI for short) and

N-methyl-v-aminopropyltrimethoxysilane (hardener 1)

in a 10000 ml three-necked flask with internal thermometer, stirrer and dropping funnel were drier No atmosphere 334 g of IPDI and 75 g of polyester-based polymer plasticizer (molar weight 492, OH number <10) submitted. The contents of the flask were cooled with an ice bath and the aminosilane was slowly added dropwise left that the temperature of the flask inside did not rise above 40 ° C.

After the total amount of 290 g had been added, stirring was continued for 10 minutes and then according to DIN 53 185 the NCO content was determined by titration.

Theory: 9.05% NCO found: 9.1-9.3%.

; ^ j The product obtained is one under Fcuchiigkciisschiuli iagcrstabilc. colorless liquid with a viscous

J sits from 3,730 mPa · see at 25 "C.

i; t.2 adduct of IPDI and N-methyl-v-aminopropylmethyldimelhoxysilane (hardener 2)

;, j This product was manufactured in a completely analogous manner to that described under 4.1 and is also available under

■ Exclusion of liquid storage unstable.

NCO content: 9.4% theoretically. 9.5% found.

J

4.3 Adduct of IPDI and N-cyelohexyl-v-aminopiopyltnmclhoxysilane hardener 3)

This adduct can also be prepared by the above method and is stable in storage at the end of its life.

π NCG content: 8.7% theoretical. 8.7% found. jo

y 4.4 Adduct of IPDI and Nn-octyl- ^ aminopropyltrimethoxysilun (hardener 4)

:: This adduct can also be produced analogously to 4.1 and is stable in storage with the exclusion of moisture.

π NCO content: 7.45% theor. 7.2% found.

y 4.5 Adduct of toluene diisocyanate (TDI) and N-methyl-v-aminopropylirimethoxysilane (hardener 5)

ρ This adduct was made from the above components only, without dilution by polymer plasticizers

Ä produced. Even with the exclusion of moisture, it can be kept for a few days at the most and was immediately after

j | processed further during manufacture.

ff NCO content: 11.44% theoretically. 11.5% found.

I J5

S 4.6 Adduct of methylene-bis-phenyl isocyanate (MDI) and N-methyl-.i'-aminopropyltrimethoxysilane

g (hardener)

B This adduct was produced analogously to 4.5 without plasticizer and processed further immediately. It is also

i {| not stable in storage. w

NCO content: 9.5% theoretically. 9.6% found.

4.7 Adduct of PES I and hardener I (hardener 7)

In a 100 ml flask with an internal thermometer. The stirrer and the dropping funnel were placed in a dry N. 'Atmosphere, 500 g (ie approx. 0.25 mol) of PES I and 0.2 ml of dibuiyl / inner dilaurate (DBTL) and heated ^{to 70 s C.} With stirring, 285 g (approx. 0.6 mol) of hardener 1 were added dropwise and the progress of the reaction was followed titrimetrically (NCO titration according to DIN 53 185).

After about 3 hours the NCO content had decreased to 0.49% and the reaction had ended. The product obtained in this way is colorless and stable on storage if atmospheric moisture is excluded.

Viscosity at 25 ° C approx. 600,000 mPas
80 ° C approx. 700OmPa S.

4.8 Adduct of PES 2 and hardener! (Hardener 8)

Analogous to the procedure described under point 4.7, 800 g of PES 2 became 0.2 ml of DBTL and 250 g Hardener 1 made an adduct. This product is even more viscous than Hardener 7 and has only limited storage stability.

A3 adduct of IPDI and N-methyl -; ^ aminopropyl-iris (methoxydiglycol) -silane (hardener 9)

The adduct was made from 33.3 g (0.15 mol) of IPDI in 5.0 g of polyester-based polymer plasticizer (molar weight 492. OH number <10) and 68.55 g (0.15 mol) N-methyl -; - aminopropyltris (methoxydiglycol) -silane analogous to that under 4.1 procedure described. b5

NCO content: 6.0% theoretically. 63% found.

4.10 Adduct of IPDl and / mercaptopropylsilane (hardener 10)

In ehern 100-ml Erlenmeyer flask, 22.2 g (0.1 mole) of IPDI and 0.1 g DBTL were introduced and heated to about 60 ⁰ C. While stirring with a magnetic stirrer, a total of 19.0 g (o.i Moi - / - fvicrcapiupropylsilan are added in small portions and left to react for a total of 3 hours.

NcO content: 10.1% theoretically. 10.4% found.

4.11 Adduct of ethylene-bis-phenyl isocyanate (MDI) and - mercaptopropylsilane (hardener 11) ο

In a 100 ml three-necked flask with an internal thermometer. The stirrer and dropping funnel were placed in a dry N2 atmosphere, 270 g of an MDI with equivalent gcw. 135 (instead of the theoretical value for pure MDI of 125), ^{heated to 70 D} C and 190 g (1.0 mol); '- Mcrcaptopropylsilan allowed to drop. The reaction had ended after 2 hours. The product is not stable in storage.

NCO content: 7.9% theoretically. 6.6% found.

4.12 Adducts from Luphen 1220 (polypropylene glycol; see point 3) and hardener 1 _t Two adducts were produced, namely

4.12.1 Molar ratio of polyether to hardener 1 is 1: 3, i.e. stoichiometrically complete (for comparison) 120 g polyether (0.0245 mol). 34.3 g hardener 1 (0.0735 mol).

4.12.2 The molar ratio of polyether to hardener I is 1: 2

120 grams of polyether (0.0245 moles). 22.8 grams of hardener 1 (0.049 moles).

The batches were each run in a dry Ni atmosphere at 70 ° C. and catalyzed with 0.2 g of DBTL. After a reaction time of 2 hours in each case, the reaction was complete, so that no more free - NCO was detectable.

5. Application examplesc test methods

a) 180 ° peel strength was determined based on the test method of the Pressure Sensitive Tape Council (PSTC), Test method PSTC-I tested: A 36 μ thick polyester film was applied over an area of 2 × 1 inch (5.08 χ 2.54 cm) stuck to adhesive-coated sheet steel and using the standardized rubber pressure roller with 4.5 Ib. Support weight securely retracted. The cell in which a 500 g weight is measured was measured stuck on strips over the entire length of 5 cm. The information is in each case mean values 3 measurements.

b) Shear strength was tested on the basis of PSTC-7: bonded area 1 square inch (2.54 2.54 cm); Load 1000 g; room temperature,

Data are mean values from 3 measurements. The tests were terminated after 48 hours.

c) Heat resistance based on PSTC-7:

Bonded area 1 square inch (2.54 254 cm); Load 200 g; Heating rate 4 ° C / min each Double determination.

d) Tack according to PSTC-6.
Data are mean values from 5 measurements.

The components were mixed and applied to steel sheets at 80 to 100 ° C. For crosslinking the coated metal sheet was exposed for 60 minutes at 120 ° C. and before being bonded to the polyester film stored for at least 2 hours at room temperature. Unless otherwise stated, the order was placed of the adhesive with a 36 μ doctor blade onto the steel sheet.

Table 1 shows results with combinations of the polyester mixtures PES-M 1, PES-M 2 and PES-M 3 with Hardener 1 is listed, the information for 0% hardener serving as a comparative example.

Table 1

Hardener 1

PES-M 1

I ¹ ESM 2

PES-M 3

Amount, wt.% 0 100 100 100 Peel strength 4sec 2 sec 38 sec Shear strength loosec 8 sec 5 min Thermal land assets, ° C 25th 20th 53 Inherent tack, cm 3.8 1.9 > 20 Amount,% by weight 5.0 95.0 95.0 95.0 Peel strength 225 sec 24 sec 29 min Shear strength 2 hours. 16h 32h Heat resistance, ° C 135 150 approx. 240 Inherent tack, cm 3.8 3.8 > 20 Amount,% by weight 73 92.5 92.5 92.5 Peel strength 115sec 27 sec 225sec Shear strength 30h > 48h > 48h Heat resistance, ° C 225 210 approx. 240 Inherent tack cm 9.1 IU > 20 Amount,% by weight 10.0 90.0 90.0 90.0 Shear strength wedge - > 48h > 48h Lot. % By weight 12.5 87.5 87.5 87.5 Peel strength wedge 84 sec 28 sec falls off Shear strength wedge > 48h no longer no longer checked checked Heat resistance. ^c C 235 no longer no longer checked checked E. intrinsic stickiness, cm 83 7.6 > 20

10

15th

20th

As can be seen from the data given in Table 1, the Polyesiermischungen used are unsuitable on their own as a pressure-sensitive adhesive due to their completely inadequate cohesion. The invention With an increasing content of alkoxysilyl groups, mixtures rapidly build up the desired cohesion without however, to an undesirable extent to lose inherent tackiness. At the same time, a very high one is strived for Heat resistance achieved.

Further combinations of the polyester mixtures PES-M I and PES-M 2 with other hardeners and those with them The results obtained are shown in Table 2. The corresponding blind tests are analogous to the table I refer to.

Table 2

JO

35

• 40

Harder type

Hard 2

I ¹ IiS-M I

Hardener 5 PKSMI

Hard b PES-Ml

Amount, parts by weight peel strength, sec shear strength Heat resistance. ° C inherent tack, cm

Amount, part by weight of peel strength, sec shear strength Heat resistance, ° C inherent tack, cm

7.5

12.5

92.5 5.0 95.0 5.0 95.0 170 47 45 > 48Sld. 7.5 hours 3 hours. IbO 155 105 11.8 4.1 6.0 87.5 7.5 92.5 7.5 92.5 185 20th 24 > 48Sld. > 48 hours 20 hours 200 200 200 > 20 7.7 6.0

53

bO

Harder type

Hardener 7 PES-MI

Harder PES-M 2

Hardener 9 PES-M 1

Amount, parts by weight 5 Peel strength, sec Shear strength Heat resistance. "Intrinsic tack. Cm

3.0

6.0

15.0 3.0 15.0 5.0 95.0 70 83 125 20 hours > 48 hours 25 sec 180 230 50 4.7 3.4 13th 15.0 6.0 15.0 125 875 9.6 45 25th > 48 hours > 48 hours 12 hours 220 approx. 240 190 65 4.9 135

Lot. Parts by weight peel strength, sec shear strength Heat resistance. ° C inherent tack, cm

The adducts of polyether and hardener 1 described under point 4.12 were applied in a thin layer to metal sheets applied and cured at room temperature for 48 hours by humidity. It turned out that the stoichiometrically alkoxysilylated product 4.12.1 cured to a tack-free film. As from the ^ i.gang was to be expected. however, the material has no strength and is practical for Applications unusable. The material described under 4.12 ^, which was only 66% alkoxysilyl-terminated, cured to a film with the following self-adhesive properties:

Peel strength wedge 1 see Shear strength > 48 hours Heat resistance "C 160 Inherent tackiness > 20 cm.

10

Claims (1)

Patent claims: 1. Pressure-sensitive adhesive based on crosslinkable, at temperatures below 100 ⁰ C liquid resin mixtures of hydroxyl-containing polymers with a molecular weight of 500 to 30,000. Characterized in that it consists of A) the liquid resin mixture, if appropriate. B) suitable, accelerating the crosslinking reaction. Catalysts and optionally C) suitable, inert diluents such as solvents. Plasticizers, pigments and fillers,